A kinetic model of aqueous-phase alkali hydrolysis of 2,4,6-trinitrotoluene

Abstract

Alkali hydrolysis of 2,4,6-trinitrotoluene (TNT) was studied using batch experiments with starting pH values 11 and 12 in glass conical flasks covered with aluminum foil. Isothermal (25 and 40 °C) as well as non-isothermal experiments were conducted. Experiments starting at pH 12 resulted in >95% reduction in the concentration of TNT; those starting at pH 11 had a maximum reduction of 20–25% in TNT concentration. In all the experiments, one major stable intermediate was produced but it could not be identified. The experimental data were used to determine the overall stoichiometry of TNT and hydroxyl ions. Approximately 100 mol (standard deviation 11.4) of hydroxyl ions were consistently consumed per mole of TNT. However, control experiments showed that all but 13 mol (standard deviation 2) of hydroxyl ions were consumed in reactions not related to TNT. A simple kinetic model involving formation of the intermediate was proposed to account for changes in concentrations of TNT and hydroxyl ions. The rate constants and activation energies of the reactions were identified using isothermal data and the kinetic model was then used to predict the experimental data in the non-isothermal experiments reasonably well.